crossref cited-by not showing citation numbers

[gosandrago]

Hi there,
I've seen some questions about missing citation numbers for scopus with this plugin. For me scopus is working fine but crossref is not.
e.g. https://www.genresj.org/index.php/grj/article/view/genresj.2020.1.4-16

I contacted Crossref, they said I dont have to apply for cited-by anymore and i can just use my normal crossref user login for the plugin. Any idea what's wrong?

Thanks for your help
Sandra